Most countries generate radioactive waste, and everyone has a vested interest in high-level nuclear waste being stored safely. High-level nuclear waste, initially comprised of extremely hot spent fuel rods, is cooled down in temporary storage pods. These can then be stored indefinitely above- or below-ground in remote areas. Underground storage may seem to be a safer option. But is it a permanent solution for the thousands of years that are necessary? Associated questions also remain about the environmental impact of nuclear power generation. There is the risk of contaminating ground water if burial occurs in deep holes. Underground sites must have dry surroundings in order to reduce the risk of water seeping through rock and corroding radioactive waste containers. In the United States, the proposed Yucca Mountain nuclear waste storage facility was to be located 1600 feet under the empty Nevada desert. Despite the government investing billions of dollars in the project, it was cancelled in 2009 due to public and political opposition. The expense of finding and constructing suitable storage facilities is particularly acute for small countries. Many options have been considered, including burying waste under the ocean floor or under the polar ice. Each potential solution is problematic. Conducting the necessary monitoring beneath the sea floor, for example, would be very difficult.